Anrtibiotics Breed Drug-Resistant Bacteria In Pigs

After giving pigs a low-dose of antibiotics for just two weeks, researchers detected a drastic rise in the number of E. coli bacteria in the guts of the animals. And those bacteria showed a large jump in resistance to antibiotics.

The particular strain of E. coli detected in the study was not pathogenic to pigs or humans. But the results add to concerns that regular use of antibiotics in farm animals could spread dangerous and drug-resistant varieties of bacteria throughout the environment and into our food and water.

The new findings also emphasize the need to find ways to keep animals healthy without antibiotics.

"We wouldn't have been surprised that bacteria shift populations or that resistance genes changed," said Thad Stanton, a microbiologist at the USDA Agricultural Research Service's National Animal Disease Center in Ames, Iowa. "We were a little surprised by how much E. coli populations went up in the medicated group. We were so surprised that we did a repeat experiment in culture. And the number went up by 20 to 100-fold. That's a big change."